Electric switch



p 1962 M. APSTEIN 3,052,185

ELECTRIC SWITCH Filed July 2, 1954 INVENTOR Maurice Apsfein ATTORNEYS wP it States i Filed July 2, 1954, Ser. No. 441,190 2 Claims. (Cl.102-28) (Granted under Title 35, U.S. Code (1952), see. 266) Theinvention described herein may be manufactured and used by or for theGovernment for governmental purposes without the payment to me of anyroyalties thereon.

The present invention relates to electrical circuits for supplying largeamounts of power to utilizing means. More particularly, it is anelectrical switch or air thyratron which is capable of completing anelectrical circuit within a few microseconds following receipt of afiring signal.

It is known that the products of combustion resulting from the explosionof a primer will ionize the space immediately surrounding the primer. Itthen two terminals of a circuit are located near to one another andwithin influence distance of the primer, the circuit can be madeconductive due to the fact that the primer, when activated, causes thespace between the said terminals to become ionized.

One object of this invention is a circuit for supplying large amounts ofpower to a load within a few microseconds of receipt of a firing signal.

Another object of the invention is a superquick switch for completingthe circuit when the power is needed.

A further object of the invention is a dependable and economical switchmeans for electric circuits.

A still further object of the invention is a compact device forsupplying large amounts of power to a load within a few microseconds ofreceipt of a firing signal.

The specific nature of the invention as well as other objects andadvantages thereof will clearly appear from the following descriptionand drawing in which:

The FIGURE is a schematic electrical circuit diagram of the invention.

It is necessary in some applications to activate a plurality ofdetonators or blasting caps within ten microseconds or less from receiptof a firing signal. This may require several thousand volts at peakcurrents in excess of one hundred amperes.

The present invention provides a dependable and economical means forsupplying great amounts of power to the utilizing means within a veryshort interval of time after the need arises. In order to maintain thecircuit normally open, the switch terminals must be consider ablyseparated in order to prevent the charge from jumping the gap betweenthe terminals. -It is apparent that to close that large gap mechanicallyin so short a time would require a tremendous amount of power. Theequipment necessary to supply that power would be unreasonably large andexpensive.

The ignition or conventional thyratron is also impractical forcompleting the circuit since a tube of suflicient size to handle such aload would be unreasonably large and would require very high power inits filament and plate circuits.

The present invention is a one shot device. it essentially destroysitself in its one use. in addition, the device is intended to be usedwhere space is at a premium. For these reasons there is a requirementthat the device be quite small and inexpensive.

In the figure, a small explosive charge or primer 7, connected in serieswith a battery 9 and a switch 10, is mounted near a pair of terminals 6.Terminals 6 are 3,952,185 Patented Sept. 4, 1962 separated by an air gapof, for example, approximately inch, and primer 7 is located at adistance, for example, of approximately /2 inch from terminals 6.Terminals 6 are connected in series between a number ofparallel-connected electric detonators 1 and a charged capacitor 4. Whenthe system is in the ready but quiescen state, capacitor 4 is in thecharged condition and preferably is charged to a substantial voltage-atleast several hundred or several thousand volts, for example. It will beunderstood that, when the system is in this state, the voltage to whichcapacitor 4 is charged will appear across terminals 6.

To fire detonators 1 by means of energy stored in capacitor 4, primer 7may be exploded by closing initiating switch 10. The products ofcombustion resulting from the explosion of the primer 7 will ionize theregion between terminals 6. Persons familiar with phenomena ofelectrical discharges through gases will understand that, if the voltageacross capacitor 4 and terminals 6 is appropriate in relation to thespacing of terminals 6, these combustion products will initiate anelectrical discharge between terminals 6. During this discharge theeffective resistance between terminals 6 is relatively low, and a largeamount of energy from capacitor 4 flows into detonators 1 in a shorttime.

It will be understood that the entire sequence of operation, from theclosing of switch 10 through the explosion of detonators 1, may be veryrapid, and that the application of a relatively very small amount ofelectrical energy to primer 7 upon the closing of switch 10 may sufiiceto cause a relatively tremendous amount of electrical energy todischarge across terminals 6 and through detonators 1.

Means which may include a generator 3 and a switch 5 may be provided forcharging capacitor 4- to ready the system for operation.

Those skilled in the art will readily understand that the primer 7 neednot be particularly powerful and tremendous mechanical ruggedness istherefore not necessary. Making terminals 6 and their supportingstructure sufiiciently rugged to withstand the detonation of primer 7can readily be accomplished with ordinary skill. In most contemplatedapplications of the invention, terminals 6 need to retain theirapproximate original posi tions only sufiiciently long to passsufficient energy from capacitor 4 to fire detonator 1.

It will be apparent that the embodiment shown is only exemplary and thatvarious modifications can be made in construction and arrangement withinthe scope of the invention as defined in the appended claims.

I claim:

1. Means for initiating a flow of current between two terminals ofunequal electrical potential and separated by an air gap, said meanscomprising: an explosive primer device located near said terminals, andmeans for exploding said primer device, said primer device beingconstructed and arranged so that the products of combustion resultingfrom the explosion of said primer device ionizes the region between saidtwo terminals thereby creating a low resistance path between said twoterminals.

2. A high power detonator-activating circuit comprising in combination:a capacitor, means for charging said capacitor to a substantial voltage,a detonator having one of its terminals connected to one terminal ofsaid capacitor, a pair of terminals spaced by an air gap connectedbetween the other terminal of said detonator and the other terminal ofsaid capacitor, an explosive primer device located near said terminals,and means for exploding said primer device, said primer device beingconstructed and arranged so that the products of combustion resultingfrom the explosion of said primer device ionize the region between saidtwo terminals forming a low resistance path therebetween, said capacitor2,331,058 Stick Oct. 5, 1943 4 Windes July 11, 1950 Mufily Dec. 30, 1952Coleman Dec. 6, 1955 Brimley et a1. Apr. 9, 1957 FOREIGN PATENTS FranceJune 24, 1953

